In measuring the concentration of a low-molecular weight compound in a complex medium, such as blood, a dialyzer is employed to produce a dialysate which is then transmitted to an enzyme bed and a measuring unit. However, during such a process, there is a possibility that the measuring unit may be influenced by other factors in the complex medium. For example, if the complex medium is blood and the concentration of low-molecular compound being measured is glucose, there is a possibility that the measuring unit may be influenced by other factors in the blood, other than the glucose, which is broken down by the enzyme bed. Accordingly, it would be advantageous to have the dialysate bypass the enzyme treatment in order that a comparison can be made to determine the zero value.
Accordingly, it is an object of the present invention to provide a method and apparatus for accomplishing the foregoing. Specifically, it is within the contemplation of the present invention to provide a method and apparatus which allows the dialysate to bypass the enzyme treatment at regular intervals so that a comparision can be made and the zero value can be checked.